Cooling of data centers

1. A cooling system for cooling racks in a data center, said system comprising: a cooling device for circulating cooling fluid in said data center, said cooling device including a fan; a plenum having a plurality of returns and an outlet, wherein said outlet of said plenum is in fluid communication with said fan, wherein said plurality of returns are configured for removing said cooling fluid from said data center and are operable to vary a characteristic of said removal of cooling fluid through said returns, and wherein said characteristic of said removal of cooling fluid through said returns comprises the direction of cooling fluid removal, wherein said plurality of returns are configured for removing cooling fluid from a plurality of racks, said plurality of racks respectively comprising enclosures configured to house a plurality of PC boards.

2. The system according to claim 1 , wherein said characteristic of said cooling fluid comprises at least one of volume flow rate and velocity.

3. The system according to claim 1 , further comprising: at least one return controller operable to control at least one of said returns, wherein said at least one return controller is configured to substantially independently control said returns to thereby substantially independently vary said characteristic of said cooling fluid removal.

4. The system according to claim 3 , further comprising: a plurality of sensors configured to sense an environmental condition within said data center, said environmental condition including at least one of temperature, humidity, pressure, and cooling fluid flow rate, wherein said at least one return controller is configured to substantially independently control said returns in response to said measured environmental condition.

5. The system according to claim 4 , wherein said plurality of sensors are configured to sense an environmental condition in locations outside of the racks and wherein the at least one controller is configured to substantially independently control said returns in response to said measured environmental condition out side of the racks.

6. The system according to claim 1 , wherein the plurality of returns includes fans configured to draw cooling fluid from the data center.

7. The system according to claim 6 , wherein the fans are movable, wherein a direction of cooling fluid removal is varied by moving the fans.

8. The system according to claim 1 , wherein the plurality of returns are independent of the racks.

9. A method of cooling a plurality of racks in a data center, said method comprising: activating a cooling system and opening a plurality of returns in fluid communication with a plenum, said plenum being in fluid communication with a cooling system, said returns being configured to remove cooling fluid from various locations of said data center; sensing the temperatures of said racks, wherein the racks comprise discrete enclosures separate from one another; determining whether said sensed temperatures are within a predetermined temperature range; and varying said removal of said cooling fluid from said racks in response to said sensed temperatures being outside said predetermined temperature range, wherein the step of varying said removal of said cooling fluid from said racks comprises varying the direction of removal of said cooling fluid.

10. The method according to claim 9 , wherein the various locations of said data center comprises a plurality of racks.

11. The method according to claim 9 , further comprising: determining whether the measured temperatures of said racks are below or equal to a predetermined minimum set point temperature; decreasing the removal of said cooling fluid from locations around said racks having measured temperatures that fall below or equal said predetermined minimum set point temperature; and increasing the removal of said cooling fluid from said racks having measured temperatures that exceed said predetermined minimum set point temperature.

12. The method according to claim 11 , further comprising: decreasing an intake of said cooling fluid by said cooling system in response to said decrease in cooling fluid removal from said racks exceeding said increase in cooling fluid removal from said racks.

13. The method according to claim 11 , further comprising: increasing an intake of said cooling fluid by said cooling system in response to said decrease in cooling fluid removal from said racks falling below said increase in cooling fluid removal from said racks.

14. An apparatus for cooling a plurality of racks in a data center, said apparatus comprising: means for activating a cooling system and opening a plurality of returns in fluid communication with a plenum, said plenum being in fluid communication with a cooling system, wherein each of said returns is configured to remove cooling fluid from various locations of said data center; means for sensing the temperatures of said racks, wherein the racks comprise discrete enclosures separate from one another; means for determining whether said sensed temperatures are within a predetermined temperature range; and means for varying said removal of said cooling fluid from said racks in response to said sensed temperatures being outside said predetermined temperature range, wherein the means for varying said removal of said cooling fluid from said racks means for varying the direction of said removal of said cooling fluid.

15. The apparatus according to claim 14 , wherein the various locations of said data center comprises a plurality of racks.

16. The apparatus according to claim 14 , further comprising: means for determining whether the measured temperatures of said racks are each below or equal to a predetermined minimum set point temperature; means for decreasing the removal of said cooling fluid from locations around said racks having measured temperatures that fall below or equal said predetermined minimum set point temperature; and means for increasing the removal of said cooling fluid from said racks having measured temperatures that exceed said predetermined minimum set point temperature.

17. The apparatus according to claim 16 , further comprising: means for decreasing an intake of said cooling fluid by said cooling system in response to said decrease in cooling fluid removal from said racks exceeding said increase in cooling fluid removal from said racks.

18. The apparatus according to claim 16 , further comprising: means for increasing an intake of said cooling fluid by said cooling system in response to said decrease in cooling fluid removal from said racks falling below said increase in cooling fluid removal from said racks.

19. A computer readable medium on which is embedded computer software, said software comprising executable code for performing a method of cooling a plurality of racks in a data center, said method comprising: activating a cooling system and opening a plurality of returns in fluid communication with a plenum, said plenum being in fluid communication with a cooling system, each of said returns being configured to remove cooling fluid from various locations of said data center; sensing the temperatures of said racks, wherein the racks comprise discrete enclosures separate from one another; determining whether said sensed temperatures are within a predetermined temperature range; and varying said removal of said cooling fluid from said racks in response to said sensed temperatures being outside said predetermined temperature range, wherein the step of varying said removal of said cooling fluid from said racks comprises varying the direction of removal of said cooling fluid.

20. The computer readable medium according to claim 19 , wherein the various locations of said data center comprises a plurality of racks.

21. The computer readable medium according to claim 19 , further comprising: determining whether the measured temperatures of said racks are below or equal to a predetermined minimum set point temperature; decreasing the removal of said cooling fluid from locations around said racks having measured temperatures that fall below or equal said predetermined minimum set point temperature; and increasing the removal of said cooling fluid from said racks having measured temperatures that exceed said predetermined minimum set point temperature.

22. The computer readable medium according to claim 21 , further comprising: decreasing an intake of said cooling fluid by said cooling system in response to said decrease in cooling fluid removal from said racks exceeding said increase in cooling fluid removal from said racks.

23. The computer readable medium according to claim 21 , further comprising: increasing an intake of said cooling fluid by said cooling system in response to said decrease in cooling fluid removal from said racks falling below said increase in cooling fluid removal from said racks.